The Depression sometimes runs in families and may be due to heredity, learned behavior or both. Even with a genetic predisposition, it is usually a stressful or unhappy life event that triggers the onset of a depressive episode. While the exact causes of depression are unknown, several factors appear to affect its onset!
I think the cause of depression is not a disease of the family and descendants of the disease in consequence with various things we experience in life that is the problem of kinship, economic problems, lack of sleep